A man walks into a bar, sits down, and asks the bartender if he'd pay the guy $20 if he could show him the most amazing thing in his life. The bartender agrees, and the man pulls out a small white mouse and a tiny piano. The mouse starts to play old man river on the piano.
The bartender isn't quite amazed yet.
So, the man pulls out a bullfrog, who starts singing along to the mouse's playing.
The bartender admits that that is the most amazing thing he's ever seen, and gives the guy his $20.
Another guy sitting next to the man sees the frog and says "Wow, I will give you a thousand dollars right now for that frog!"
The man agrees, and sells him the frog.
After the man who bought the frog leaves, the bartender sez, "Man, you must be insane. That frog could have made you a fortune."
The man says, "Not really, the mouse is a ventroliquist too."